Tout savoir sur l’ORP / Redox

ORP measurement (also called REDOX) is used to monitor water disinfection quality. The higher the concentration of ORP in water, the greater its capacity to eliminate harmful micro-organisms. The better the water quality for your health. ORP has become a regulatory standard in many countries. It is more reliable than measuring chlorine levels. This article explains what ORP is. Why it's the most effective way of determining the disinfection capacity of your pool / spa water

The ICO application lets you check measurements such as ORP, pH, TDS and water temperature on your ICO pool or ICO spa device.

Définition de l’ORP

ORP (Oxydo Reduction Potential) is an indicator of the level of disinfection of your pool or spa water. An ORP probe, notably present in vour ICO connected probe, measures the electrical potential delivered by all disinfectant chemical agents. It is expressed in milivolts. Knowing the concentration level of disinfecting agents in water allows :

  • To reduce disinfectant consumption in the case of dosing treatments.
  • To optimize chlorine production in the case of an electrolyzer, thus limiting excess chlorine.

How to get a balanced ORP

For optimal disinfection of water at 25°C, international standards recommend ORP / Redox measurements between 650 and 750mV.

What to do when ORP is too low ? : Under 650mV, the water is not sufficiently disinfectant. There is a significant risk of bacterial proliferation in the water.

  • To increase ORP, you need to increase the amount of disinfectant in the pool:
  • Result 0-30 ppm the pool/SPA does not have enough stabiliser, the REDOX drops very quickly when chlorine is added. You need to increase the stabiliser level to achieve perfect disinfection.
  • 30-50 ppm measure: ideal rate for pool/ SPA

A too high ORP : Above 850mV, chlorine becomes aggressive to the eyes and skin. This causes feelings of tightness or irritation. It can also damage your equipment and bleach your pool or spa lining.

  • 50-60 ppm measure : the level is high but still acceptable. You can simply change your disinfection method by using non-stabilised chlorine.
  • 60 ppm measure : The level is very high, you can drain part of the volume of water in the pool or SPA (by changing half the water, you will halve the stabiliser level) OR use a stabiliser reducer.

It may be that the ORP measurement is up sharply if :

  • Vous venez de faire un traitement chimique: dans ce cas la mise en route de la filtration doit réguler l’ORP dans les prochaines heures.
  • Your filter and filtration system are not clean
  • La calibration de votre sonde ORP n’a pas été effectuée récemment (vous devez vous référez aux conseils d’utilisation du fabricant).

All about ORP measures here.

Pourquoi mesurer l’ORP est plus efficace que la mesure du chlore

Pour comprendre la différence entre la mesure du chlore et de l’ORP, il faut faire la différence entre une eau désinfectée et désinfectante:

A sanitized water (chlorine measurement): we measure the QUANTITY of total chlorine present in the water. This is water that has been cleaned of potentially harmful organic matter. When water contains sufficient chlorine, it is disinfected at the moment of measurement. But this does not last! A change in temperature or pH is all it takes for water quality to deteriorate rapidly.

A sanitizing water (ORP measurement): in contrast, the ORP measurement refers to the QUALITY of the sanitizing agents present in the water. Here, we measure active (or effective) chlorine. Depending on the quantity of disinfectant available in the water, it will always be disinfected in 3 hours, 2 days or 2 weeks. It is therefore more relevant to know this value rather than the amount of total chlorine present in the water.

Mesurer l'ORP apporte une diagnostique précis du taux de désinfection de l'eau de votre piscine ou spa. C'est plus précis que les bandelettes et plus fiable.

Why choosing a connected ORP Sensor ?

By measuring the ORP, ICO gives you an overview of the disinfection quality of your pond water, unlike other analysis tools such as strips that measure the total effective chlorine or free effective chlorine .

  1. Fiabilité des mesures : l’immersion des sondes de votre ICO est à la bonne profondeur dans l’eau. Toutes les heures, l’appareil prend des mesures à plusieurs endroits du bassin pour encore plus de fiabilité. C’est la somme de plusieurs analyses qui permettent à notre sonde de faire un diagnostique précis de la qualité de l’eau, puis de faire la bonne recommandation.
  2. Analysis and treatment recommendations: our connected sensor doesn't just analyze your water. It also sends chemical treatment recommendations to your smartphone, along with the product and dosage to use. These recommendations are customized according to whether you are using tablets, liquid,...
  3. More sustainable and economical : Connected probes last several seasons and are recyclable.While the purchase of a connected probe is more expensive than strips, personalized treatment recommendations will save you the use of chemicals every year. It's a greener solution! Finally, with ICO you have a connected probe that measures all the important parameters for keeping your water balanced.
  4. Smart features: the ICO application lets you use various functions. The share function, the water index, and many more! Découvrez toutes ICO Spa main features .

Entretient d’une sonde ORP

Calibration : Calibrating your probe at the start of each season calibrates it and guarantees reliable measurements. It also helps extend the probe's lifespan, which is just one more good thing you can do for the planet! All about ICO calibration sensors.


ORP-REDOX provides direct information on disinfection quality , unlike chlorine concentration. Chlorine measurement with strips measures the total amount of chlorine present in the water. Although all forms of chlorine participate in disinfection (active, potential and chloramines), some disinfect much less than others. This is why ORP measurement is the most effective way to monitor the quality of your pond water.